This invention relates to a telephone conversion unit and to a telephone conversion unit with a multiple memory system therein.
Systems for converting a push button input to a series of pulses suitable for simulating a telephone dial are known in the art as exemplified by the General Instrument Corporation Ay-5-9100 push button telephone dialer circuit. This push button dialer circuit receives a parallel 4-bit input together with a strobe input which is generated each time a key is depressed and in response thereto provides at its output a series of pulses suitable for simulating a telephone dial.
Further, a number of patents such as U.S. Pat. Nos. 3,860,765, 3,555,201, 3,665,113, 3,670,111, and 3,735,050 disclose repertory dialers which apply telephone dialing signals to a telephone line in response to the selection of a switch corresponding to the desired telephone number. Each of these references disclose random access memories which require separate switching keyboards for selecting the particular location of the stored number in memory and for generating the signals to be stored within selected locations of the memory. Such duplication of keyboards increases the cost and complexity as well as the size of the telephone instruments. The McCabe et al U.S. Pat. No. 3,860,765 patent does disclose a single keyboard unit for controlling the storage of numbers in memory or the direct dialing of numbers via an output pulsing unit. There are, however, several drawbacks of this telephone number generator. Thus, a separate power supply is required for driving the generator, and no means are disclosed for simply inserting a conversion unit into a dial telephone in place of the dialer unit thereof. Further, this generator does not disclose an alternative to the complex mechanical keyboard switches commonly utilized in telephones. These keyboard switches are designed so that at least two mechanical switches are closed upon the depression of a single key. This results in a relatively low long-term reliability for the keyboard unit and relatively high assembly costs.
It accordingly is an object of this invention to provide an improved telephone conversion unit for converting a standard dial telephone to a keyboard controlled telephone.
It is another object of this invention to provide a telephone conversion unit with a multiple memory system for memorizing a plurality of telephone numbers which subsequently can be retrieved from memory and utilized to generate a series of pulses suitable for simulating a telephone dial.